[Physics-talks] Seminar: Reframing the Hubble Tension Through the Sound Horizon — Jan 27

[Celina Yamakawa]

Dear colleagues and friends,

You are warmly invited to attend the upcoming seminar:

*Reframing the Hubble Tension Through the Sound Horizon  *
*Speaker:* Helena Garcia Escudero (University of Southern California)
*Date:* Tuesday, January 27, 2026
*Time:* 11:00 a.m.
*Location:* Reading Room


One of the most striking open problems in modern cosmology is the Hubble
tension: the persistent disagreement between measurements of the
present-day expansion rate of the Universe obtained from local observations
and the lower values inferred from cosmic microwave background data within
the standard ΛCDM framework. This mismatch has motivated extensive scrutiny
of both late-time measurements and early-Universe assumptions.

Furthermore, this discrepancy may point to gaps in our understanding of the
physics around the epoch of recombination, where the sound horizon at
decoupling plays a central role. Because the value of the sound horizon
depends on the microphysics of the early Universe, it is crucial to obtain
empirical constraints on both H0 and the sound horizon without relying on
model-dependent assumptions. In this talk, I will present recent work
demonstrating how the combination of baryon acoustic oscillations with CMB
lensing and galaxy weak lensing and clustering enables
sound-horizon–agnostic determinations of the Hubble constant, and I will
discuss how allowing for massive neutrinos impacts the inferred value of H0.

All are welcome to attend.


-- 


Celina Yamakawa

Assistant to the Department Chair | Administrative & Events Coordinator

Physics & Astronomy Department

900 University Ave
<https://www.google.com/maps/search/900+University+Ave?entry=gmail&source=g>,
Physics Bldg. RM 3047B, Riverside CA 92521
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